I asked Sean the same question a couple days ago, he said the 500r is an older design and can't quite compare with the new Precision turbo's and suggested I went with them.

 

Same here. I was running the 1.15 6766 but spool was about the same here. DO NOT GO .84 you will sacrifice performance.
The 6766 will do all that you need

 

Thanks guys. I couldn't reach him by phone. I'm currently running the 500r and wanted to upgrade but wasnt sure if the 6766 CEA DBB was actually an upgrade since they were the same size. Any input will be appreciated.

 

500R uses a GT35 turbine wheel( 68mm) mated to a 67mm compressor wheel( To4R/Z).
6766 uses a billet 67mm compressor wheel mated to basically a new generation Ptrim wheel( 74mm).

If you really want one of those we've been making them for years, I just never thought it was a good choice for rotary( too small of a turbine wheel for such a large compressor). We call it a GT3584R.

 

Ah, that makes sense than. I wasn't aware that the 6766 was meant to make the same power as a 6266 when in the teens. I was looking at those numbers and figured that is what I would expect out of my turbo (PT6265) at that same boost level, hence my comment.

Why would the larger turbo make the same power at the same (lower) boost?

 

When both compressors are working with reasonable efficiency at set boost level, intercooler diminishes any possible difference in IAT's, so mass flow is essentially same. Only thing that could make substantial difference is exhaust backpressure, which would lower VE% in upper range and increase pumping losses, but since we're dealing with same turbine with same aero, exhaust manifold pressure also will be essentially same.

Of course, once the flow demand starts to overcome compressor capabilities, even with set boost level, engine would outflow smaller compressor, which would lead to operation with lower efficiency, higher IAT's and mainly higher backpressure - even with same turbine.

On the other hand, larger compressor having whole map shifted to the right will support flow demand of given pressure ratio with higher efficiency, which will lead to lower IAT's, lower backpressure and lower pumping losses, all vital for engine performance, reliability and durability.

 

So people can get a idea on what is what about these turbo's, as I tell everyone who calls me a "billet" compressor offers little in terms of improvement over a "cast" wheel unless the flow is needed, ie larger ports smallish compressor, or higher rpms.

As far as sizing goes, if your goal is to be a responsive car with 450whp then a 62/66 BB .84 divided S-cover is hard to beat. It offers a more efficient compressor when nearing 20psi than the 35R as well as a much better flowing turbine. The turbine will not choke off and will respond better than the 62mm 1.06 on the 35R. This will also be a good 500whp turbo if you don't mind pushing past 20psi.

A 67/66 BB is a good solid choice if you know your goal is over 500whp and your looking to get in the mid to upper mid 500's this turbo can do it and be responsive in the process versus jumping up to the larger framed turbo's. If you're on a heavily ported engine HBP or BP or even a semi-P this turbo on a H-cover is a good choice for response and as small as I would go.

A 64/66 BB is a very nice setup as it allows you a bit more compressor without a noticeable drop in response so for those wanting something more like the 67/66 but not wanting the later response time it is a good choice. Meaning If you want your 450whp responsive car but are also wanting to not push it too hard to hit your 500whp mark this turbo falls right in the middle. If I had a street FD this would be what I would run on my car on a Large SP.

As for the 500R's I made the first one back in 01 for my personal car as it was stated it was a 35R with a 67mm compressor and it made a easy 480whp on a T3 1.06 (that was all I had available at the time) on pump gas daily driven. (daily like everywhere including groceries) I hadn't called it anything back then it was a custom 35R for me. Customers kept liking the cars performance so when I thought I could throw it on a machined T4 housing I then started to move them and they performed well. The 62mm turbine is small in my opinion for anything but a street car, but honestly most of our customers were street cars and it performed much better on a divided T4 housing. The wheel ratio for a 35R is not ideal(pretty crappy actually) to begin with@1.20 and stepping up to 67 comp only bumped it up .03 so it was little lose noticed in response. When those parts became too much of a headache to service. (anyone who's owned one will tell you) I switched the 500R to a more friendlier 67/65 sizing with differently clipped wheels and A/r's. Honestly I could be like other shops (none on this board) and take off the shelf turbo's and rebadge them. ie a 64/66 could be a 500R and I have thought about it but I feel it's being misleading, sure I lose sales but so be it, and to be honest at this point call precision and ask them rotary questions, guess who they recommend

As far as power numbers go comparing them is pointless, there are so many variables (especially with everyone porting their own stuff now) that it can vary greatly.

Liborek's post is on point. If you run a smaller compressor and are leaving something on the table you will notice it by switching to a larger compressor. If you have nothing to leave on the table compressor wise you will see little to no gain by switching over, (same can be said for IC's by the way) That said all these turbo's mentioned above (minus your older cast 35R comp) will really start to wake up and perform right around 20psi and above. Turbo's in these size ranges with the current aero aren't really being best utilized in the sub 20psi range.



~S~

 

.84 /.1.0 your choice would be ,street use

 

I plan on grabbing a 6766 ball bearing version this month with a divided 1.15 a/r. It's going on a bridgeported REW street car with water/meth. I was looking at getting the S cover, but after reading this thread I'm leaning more towards the H. It's running straight into a water/air intercooler.

How much are you guys paying for these. I'm looking at getting it through TD Autowerkes as the prices seem good and they are helping me get around the import tax into Australia. (1925 for the turbo, 470 for 4 ID 2000 and 345 for a Tial MV-R Wastegate)

 

Did you fix all the issues on the car? I remember hearing the tuner telling you all the things that didn't look right and you had it on the lift/dyno.

Originally you were having problems with the car not starting. The tuner said it sounded like a crank sensor issue. You said no its fine and added a lot of timing through the power FC?


If I remember correctly there were issues with the micro tech harness you adapted to use to hook the power FC up to and this is what was part of the problem with the starting issues.

The crank sensor was wired wrong giving you 40-60+ degrees of timing

20-30 wires were just hanging all over the place, the tuner was really worried about this but you said it was fine, those wires coming from the power FCC don't do anything.

You guys discussed the issue with the exhaust manifold and waste gate that the tuner said was to small and would cause boost creep. You said don't worry it would be fine.

After all of this the tuner didn't want to tune it but you said don't worry it's fine, it's a freshly rebuilt engine.

He said okay and then it blew. When he took it apart noting inside was new. It looked like an engine with thousands of miles on it. Corner seals were flipped on the oil control rings were shot to name a few.

I heard that Sam is running your Power FC with the same Map the supposedly blew your engine. Although Sam has had no issues with the tune from that map.

 

You know 99% of engines blow due to human error, negligence, or simply lack of knowledge... The seals don't just break on their own accord lol.

thewird

 

Did he tell you this stuff? Well he is full of sh*t lol, sam is not running my pfc, and also the only issue with the car was the backwards trigger wire, and we fixed it before we broke the engine in, the car was driving great as much i can clean up with the commander, i raised the boost cut to 8 psi it was cutting fine on the street, drove great to dyno, replaced the oil on the lift and spark plugs and checked the vacum lines and connections.
Any how tell him he is lucky this didn't happen few years ago lol

 

By the way me and Sam build that engine

 

Any big numbers with this turbo yet. Anybody?

 

bump for updates

 

Cant go wrong with this turbo on street,
I have pushed it up to about 10-12 pounds on spring pressure love the turbo very responsive and pulls hard, I did go with .96 udivided t4 with short undivided manifold I made, had the divided .84 ar ditched it, the manifold that my pfc tuner made for me was hitting, project slowed down with coolant seal wetting the plugs, after they were clearing up the car pulled hard, I should have never listened to my pfc tuner, I was going to have him use a new seal but he insisted and talked me out of it he said he reuses the coolant seals all the time with no problem after flooding them with silicone,
got another engine I freshened up in the car its almost ready for boost, hope to have some numbers in next couple weeks

 

I should have some numbers before too long.

 

I got retuned before TX2K13 with my new manifold and fixed some vacuum leaks and my new low boost tune at 20psi was 473whp on a mustang dyno and at 25psi it was 530whp. Both of the tunes my twin plate clutch was slipping (its pretty old so I'm assuming I need new disks) so I'm assuming it would've made more. I couldn't get to 30psi because the clutch was getting weaker and weaker on the dyno. My spool time also decreased though, I get full boost at 3900rpm now so the powerband is a lot better and the car is significantly faster than before (more than the numbers suggest). It still roasts my 295/30/18 r888s in second and third gear. I haven't had a chance to test it out against my friends' cars yet, but it should hold its own pretty nicely.

 

Once again no official times, but I finally did a 45-150 run against my friend with a supercharged 2011 5.0 making 700whp and I walked him on my 20psi tune. My clutch hated me at the end of my run though, but it was very nice run. I'm extremely pleased with this turbo, I didn't even brake boost but still got about a 1/2 car jump on him from my turbo spooling quick enough.

 

, can't wait for my 6266! Any vids?

 

I wish I did, my go pro wasn't charged up apparently.

 

Would you recommend a 1.00 or 1.15 on the 6466?

 

I made 644whp on a 6766 turbo at 30 psi. Turbo is plenty strong with great response .

 

smg944

what mph have you run with that power ?

 

Didn't get to take it to the track last year. But going by vbox run should have been high 140s